The present disclosure relates to compositions and articles containing a propylene-based polymer and processes for producing the same.
Worldwide demand for propylene-based polymers continues to grow as applications for these polymers become more diverse and more sophisticated. Known are Ziegler-Natta catalyst compositions for the production of olefin-based polymers. Ziegler-Natta catalyst compositions typically include a procatalyst containing a transition metal halide (i.e., titanium, chromium, vanadium), a cocatalyst such as an organoaluminum compound, and optionally an external electron donor. Ziegler-Natta catalyzed propylene-based polymers often lack the desired stiffness. Given the perennial emergence of new applications for propylene-based polymers, the art recognizes the need for polymerization processes that produce propylene-based polymers with improved and varied properties. Desirable would be polymerization processes for the production of propylene-based polymers that exhibit high stiffness.